What to expect in Great Barrier Reef in September
September is a strong choice for Great Barrier Reef: 27° / 19°, with the biggest crowds of the year and prices close to the yearly average.
Great Barrier Reef weather in September
Typical conditions in Great Barrier Reef during September, based on long-run climate normals rather than any single year. Treat it as a planning guide, not a forecast.
| Average high | 27°C 81°F |
|---|---|
| Average low | 19°C 66°F |
| Rainfall | Dry 15/100 |
| Total rainfall | 35 mm1.4 in |
| Rainy days | 7 |
| Sea temperature | 25°C 77°F |
| Daylight | 12 h |
| How it feels | Warm and comfortable |
Rainfall figures are for Cairns.
Average highs sit around 27°C with lows near 19°C. It is one of the drier months — pack light.
Crowds & demand
Crowd levels are High for Great Barrier Reef — the biggest crowds of the year.
Prices & value
This month counts as shoulder season: prices close to the yearly average.
What to pack
Light layers for 27°C days and something with sleeves for evenings, which cool to around 19°C. Rain gear is largely optional this month, which keeps your bag light.
What it costs
Costs in September sit around the yearly average for Great Barrier Reef — neither a bargain nor a squeeze. Booking a few weeks out is usually enough. Compared with the most expensive month of the year, you are looking at roughly 7% less.
Who this month suits
- Travellers who want the most reliable weather
- Anyone travelling on a budget
- Visitors who want to catch a festival
Events & what’s on
Look out for Whale Migration Season, Cairns Festival while you’re there.
- Whale Migration Season — Humpback and minke whales migrate past the reef, drawing dedicated watching tours.
- Cairns Festival — A multi-week arts and cultural festival fills the Cairns Esplanade with performances.
Great Barrier Reef in September compared with nearby months
If your dates are flexible by a few weeks, this is what shifting them actually buys you.
| Month | Temp | Crowds | Price | Score |
|---|---|---|---|---|
| July | 25° / 17° | High | $$ | 57 |
| August | 26° / 17° | High | $$ | 53 |
| September · This month | 27° / 19° | High | $$ | 56 |
| October | 29° / 21° | Moderate | $$ | 60 |
| November | 30° / 23° | Moderate | $$ | 62 |
These months score higher for Great Barrier Reef on the same blend of weather, crowds and price. Same destination, better odds.
Or go somewhere else in September
If the destination is negotiable but the month is not, these places are at their best in September.
Figures are climate normals and modelled estimates — a planning guide, not a forecast. We separate fact, estimate and recommendation. Updated October 2026
